In a bowl, whisk flour, salt, and sugar. Cut in the cold butter with your fingers or a pastry cutter until it looks crumbly. Add egg yolk and mix just until it starts to clump. Press the dough into the bottom of a 9-inch springform pan. Prick with a fork and chill while you make the filling.

In a large bowl, blend queso blanco and sweetened condensed milk until smooth. Add eggs one at a time, beating well after each. Stir in vanilla and lime zest.

Preheat your oven to 325°F (163°C). Pour the filling over the crust. Bake for 50–55 minutes or until the center is just set and the edges are lightly golden. Cool to room temp, then refrigerate at least 4 hours or overnight.

In a saucepan, heat guava paste with water and cachaça (or rum) over medium-low heat. Stir constantly until it melts into a thick sauce. Cool slightly, then pour over the chilled cheesecake. Spread it gently to the edges.

Let the cheesecake sit in the fridge for another 30 minutes so the guava layer sets. Then slice, serve, and prepare for compliments.